Construction for supporting the rotatable members of a piano action mechanism employing carbon fiber mixed bushing cloth

ABSTRACT

A piano action mechanism wherein a shaft pin for rotatably supporting the rotatable members on a flange is wound with bushing cloth containing carbon fibers having high lubricity and increased durability.

United States Patent 1 1 1 1 3,730,963 Imagawa 51 May 1, 1973CONSTRUCTION FOR SUPPORTING [56] References Cited THE ROTATABLE MEMBERSOF A PIANO ACTION MECHANISM UNITED STATES PATENTS EMPLOYING CARBON FIBERMIXED 1,823,142 9/1931 Hickman 84 251 BUSHING CLOTH 2,580,438 1/1952Knoblaugh ..308/238 Inventor: Katsuhiko g Hamakita 3,565,127 2/ 1971Nlcely ..l39/426 Japan OTHER PUBLICATIONS [73] Assignee: Nilfpon GakkiKabushiki Graphite Now Processed In Flexible Textile Hamatsushbshlzuoka'keni Form-Applications Limitless, Mechanical Engineer- Japaning, June 1959, page 121. 22 Filed: Dec. 27, 1971 PrimaryExaminer-Richard B. Wilkinson [21] Appl' 2l20l7 AssistantExaminerLawrence R. Franklin Attorney-Robert D. Flynn et al. [30]Foreign Application Priority Data Dec. 30, 1970 Japan ..45/133764 [57]ABSTRACT A piano action mechanism wherein a shaft pin for UaS- rotatablyupporting the rotatable members on a [51] Int. Cl. ..Gl0c 3/18 flange iswound with bushing cloth containing carbon [58] Field of Search ..84/251 452;

fibers having high lubricity and increased durability.

3 Claims, 3 Drawing Figures Patented May 1-, 1973 Y BACKGROUND OF THEINVENTION This inventionrelates to a piano action mechanism, and moreparticularly to aconstruction:fonsupporting the rotatable parts thereof.

Whether of a grand or upright type, a piano'has its action mechanismprovided with a bearing section for enabling the parts of the actionmechanism.to be freely rotated. This bearing section is so constructedas to permit smooth operation of the rotatable parts of the actionmechanism. With a conventional piano, the bearing sectio'n is providedwith :bushings consistingof felt rings, the surface of whichis-coatedwith silicone-or impregnated with suds or soapy water. However, abearing section having such .a construction has the drawback that itwill lose lubricity-during'long use.

It is accordingly the object of thisjinventionto provide a constructionfor supporting the rotatable partsof a piano action mechanismvwhich'is'least likely to:lose lubricity during-longuse.

SUMMARY OF THE INVENTION According to an aspectofthis invention, thereis provided a construction for supportingthe rotatable parts of a pianoaction mechanismwhich comprises asupport member having a pair of legportions perforated with mutually facing shaft holes, the-leg portionsbeing arranged parallel to each other there'bydefining a hollow spacetherebetween; .a rotatable memberdisposed inthe hollow space of thesupport member and provided with a shaft pin passing through the shaftholes formed in the support member; and bushing means containing carbonfibers, the bushing .means being wound about the parts of the-shaft pinwhich are inserted into the shaft holes.

According to this invention, the bushing means wound about the shaft pincontain carbon-fibers having high lubricity and increased durability,thereby maintaining the prominentlyimproved smooth movement of therotatable membersfor a long period.

BRIEF DESCRIPTION'OF THE DRAWINGS FIG. 1 is a side view of anordinary'upright piano action mechanism, partly insection; r I

FIG. 2' is anexploded perspective view of a bearing section accordingto-this invention adapted for use with the piano action mechanism ofFIG. 1,.bushing cloth being inserted in the shaft holes bored inasupport member so as to be cut in the bushing; and

FIG. 3 is a perspective view of the support member with the bushingsinserted intheshaft holes.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the actionmechanism of an upright piano. Though well known, the action mechanismwill now be briefly described for a better understanding of thisinvention. Below a fixed central rail 11 is disposed a wippen assembly12 swingabl-y supported bymeans of v a flange 13. The wippen assembly 12is selectively operated by a capstan button 14 urged by a keyboardmechanism (not shown) in the direction of the inthe above-mentionedconstruction. The butt 20,*which.

.15 as the result of the swing of the wippen assembly 12,

bringing adamper 17 out of contact with a string 18, so that the string18 is fully vibrated by being struck by a hammer22. To the central rail11 is'further fitted a butt flange 1'9,'which iri turn rotatablysupports a butt 20. On thebutt 20 is erected a shank '21 provided withthe hammer 22 at the end. To the wippen assembly 12 is conn'ected'a jackflange 23, towhichrthere is rotatably fitteda jack 24. This jack24'rotates asthe result-of the swingof thewippen assembly 12. Therotation of the jack24leads to the swing ofthe butt 20, therebycausingthe'hammer 22 to strike the string 18.

'In'the aforementioned piano action mechanism, the rotatable memberssuch as the wippen assembly 12, damper lever 16, butt 20 and jack 24have to be rotatably supported by the associated flanges. This inventionis intended to improve such a rotatably supportingmechanism.

There *willnow be described by reference to FIGS. 2 and 3 a mechanismaccording to this invention for rotatably supporting the aforesaidrotatable parts. Referring to FIGS; 2and3, the butt flange 19 is takenas an exampleofthe various flangesfor supporting the rotatable parts asshown in FIG. 1 It will be noted that the other'flanges'are ofsubstantially the same construction. As shown in FIG. 2 the flange 19has a pair of parallel leg portions 27 and 28 formed at one end whichjointly-define a hollow'space 26. The leg portions 27 and .28 are boredat the center with shaftholes 29 and 30 facing each other through thehollow space 26.

.natural'fibers-such as wool with which there are mixed carbon fibershaving high lubricity, the carbon fibers being trapped on the surface ofthe fabric. Those parts of the bushing cloth which are not locatedwithin the shaft'holes 29 and 30 of the flange l9 are then cut off,

the shaft so that bushings 31d, and 31b are disposed in holes 29and 30as shown in FIG. 3. i

The rotatable butt 20 is thenfitted'to the flange 19 of is also boredwith a'hole (the butt being omitted from FIG. 2to simplify the drawing),is placed in the hollow space 26 defined betweenthe leg portions 27 and28 in such a manner that the hole of the butt 20, and the shaft holes 29and 30 of the paired leg portions 27 and 28 are linearly aligned.Thereafter there is introduced a shaft pin 32 through the. linearlyaligned holes, obtaining the construction of FIG. 1 for rotatablysupporting the butt 20. The supporting construction for the otherrotatable parts is formed in a similar manner.

For the object of this invention, bushing cloth wound about the shaftpin by being inserted into the shaft holes may be a fabric or clothwoven from the warp of carbon fibers alone and woof of natural fiberssuch as wool, and viceversa, followed by napping.

What is claimed is:

1. A construction for rotatably supporting a,piano action mechanismwhich comprises a supporting member having a pair of leg portionsperforated with mutually facing shaft holes, said leg portions beingarranged parallel to each other, thereby defining a hollow spacetherebetween; a rotatable member placed in said hollow space of saidsupporting membervand provided with a shaft pin passing through saidshaft holes of said supporting members; and bushing means comprised of afabric containing carbon fibers, said bushing means being wound aboutthe parts of said shaft pin which are

2. A construction according to claim 1, wherein said bushing means is afabric woven from Mixed spun yarns of wool fibers and said carbonfibers, said fibers being napped on the surface of the fabric.
 3. Aconstruction according to claim 1 wherein said bushing means is a fabricwoven from warp and woof, at least one of the warp and woof consistingof said carbon fibers alone, said fibers being napped on the surface ofthe fabric.